American citizens have a lot of protections under Constitutional and federal law. Visitors have a lot fewer protections. Her citizenship didn't make the crime, it just made it worse.
Not only American citizens; as a green-card holder I have almost all of the same rights, the only right I don't have is the right to vote. I have the exact same constitutional rights as everyone else, even though I am a resident alien in this country.
A citizen can't be deported for any reason, ever. And I'm sure there are other differences.
Well when you start pissing off the people that like to scream "I'm an American!" then there's a fighting chance that things can change.
That's exactly the point that irked me. Would she find it ok, if it was done to her in say Europe.